This has been my experience as well; Spotify is great for pop music and more mainstream things.
If one day you want a song that isn't on spotify, but it is on a free bandcamp download, the whole house of cards crumbles (for me anyway).
If I have to keep iTunes around for random songs, I start to just buy albums through that, and then I end up rarely using spotify.
Spotify has a huge selection, to be sure, and for most people it's more than enough, but there will always be someone who isn't quite covered by the catalog and they will generally just go back to using itunes / foobar / whatever.
Why don't you just download the song and import it into Spotify? Spotify plays it like any other song and will even sync it with your devices like normal songs.
If one day you want a song that isn't on spotify, but it is on a free bandcamp download, the whole house of cards crumbles (for me anyway).
If I have to keep iTunes around for random songs, I start to just buy albums through that, and then I end up rarely using spotify.
Spotify has a huge selection, to be sure, and for most people it's more than enough, but there will always be someone who isn't quite covered by the catalog and they will generally just go back to using itunes / foobar / whatever.